The reason I only have 2 posts is because I normally go on reddit instead of these forums, I have played the game for thousands of hours and have owned the game since beta. I don’t have a way to prove to you that “MMR lock-in” as you call it isn’t a thing that doesn’t break TOS, so let’s just go with the ways that are. A little while back I was a booster, I’m not proud of it but I needed the money desperately. So I would recieve accounts that were say, 1400 SR and told it needs to be diamond. The first few games in would play I would get like 15 SR even if my stats were exceptional. This is because the MMR for the account I was playing on was negative, so the game was trying to “force” them downward. This is what you call “lock-in”, the game trying to keep you at your SR or lower, yes it is a thing. It is caused by stats in game to be lower than the average player of your SR playing your same hero. For example if I’m at 1800 SR and I have less healing, less damage, and more deaths than most moiras at 1800, even if I win the game can only assume I am undeserving of my rank and it will shift my mmr slightly downward. However, it does not take very long at all, maybe a couple hours, for the game to realize that I’m playing much below my skill tier and adjust the mmr to compensate. By the time I’m reaching gold I’m earning 75 SR for a win and losing 10 if I lose. When I say “MMR-lock in” isn’t a thing, I say it because I have seen people throw accounts away because they think it’s irredeemably hard stuck at whatever rank because of the skill based SR system.
I have given up boosting for a more ToS friendly coaching, hmu if you want a free session. Vargalf#7653 on discord.